On Tue 03-02-15 11:16:00, Mel Gorman wrote: > On Tue, Feb 03, 2015 at 09:19:15AM +0100, Vlastimil Babka wrote: [...] > > And if we agree that there is indeed no guarantee, what's the actual semantic > > difference from MADV_FREE? I guess none? So there's only a possible perfomance > > difference? > > > > Timing. MADV_DONTNEED if it has an effect is immediate, is a heavier > operations and RSS is reduced. MADV_FREE only has an impact in the future > if there is memory pressure. JFTR. the man page for MADV_FREE has been proposed already (https://lkml.org/lkml/2014/12/5/63 should be the last version AFAIR). I do not see it in the man-pages git tree but the patch was not in time for 3.19 so I guess it will only appear in 3.20. -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>